Arrangement for converting a rotational movement in one direction into a tangentially oscillating movement about a shaft or conversely



P 1958 J. M. CLUWEN 2,852,709

ARRANGE T FOR CONVERTING A ROTATIONAL MOV NT IN ONE RECTION INTO A TANGE ALLY OSCILL NG MOVEMENT ABOUT A SH CONVERSELY Filed Oct. 1955 WNW INVENTOR JOHANNES MEYER CLUWEN AGENT United States Pa fl ARRANGEMENT FOR CONVERTING A ROTA- TIONAL MOVEMENT IN ONE DIRECTION INTO A TANGENTIALLY OSCILLATING MOVEMENT ABOUT A SHAFT OR'QONVERSELY Johannes Meyer Cluwen, Eindhoven, Netherlands, as-

signor, by memo assignments, to North American Philips Company, Inc., New York, N. Y., a corporation of Delaware Application October 4, 1955, Serial No. 538,483

Claims priority, application Netherlands October 13, 1954 4 Claims. (Cl. 310-99) An arrangement has already been suggested for converting a rotational movement in one direction into a tangentially oscillating movement about a shaft, or conversely, by means of at least two separate parts which are magnetically coupled together by permanent magnets. In such arrangements use is made of an oscillation having a deflection of a limited value only.

The object of the invention is to convert or obtain an oscillation having a large deflection.

According to the invention, the arrangement is characterized by a first part which always rotates in one direction, a second part which always rotates in the opposite sense due to its being mechanically coupled to the first part, and a third part which performs the tangentially oscillating movement and which during one direction of movement is magnetically coupled to the first part and slips with respect to the second part, but during the opposite direction of movement is magnetically coupled to the second part and slips with respect to the first part.

A very effective conversion of movement is thus possible, since during the slipping of two parts with respect to each other substantially no moment is transferred from one part to the other. Despite the oscillatory motion of one part, this part is with each direction of movement coupled to one of the other parts, so that transfer of the couple in the proper direction takes place at any moment.

In order that the invention may be readily carried into effect, it will now be described, by way of example, with reference to the accompanying drawing, showing two embodiments thereof.

Fig. 1 shows an arrangement according to the invention for converting a tangentially oscillating movement about a shaft into a rotational movement in one direction and Pig. 2 shows a similar arrangement for conversion of the movement in the opposite sense.

In Fig. 1, parts 1, 2 and 3 comprise disc-like magnets of permanent-magnetic material in which poles N and S magnetised in the axial direction produce a magnetic field of alternately varying direction as measured along a pitch circle. The parts 1 and 3 each comprise one magnet and the part 2 comprises two magnets. It is alternatively possible to provide part 2 with only one magnet. The magnets of the parts 1 and 3 are connected to conical wheels 4 and 5 of highly magnetic material, so that these poles of the circuits of parts 1 and 3 which are remote from part 2 are magnetically connected. The conical wheels 4 and 5 are connected by a conical wheel 6 in such manner that during rotation of the wheel 6 the wheels 4 and 5 rotate in the opposite sense. The part 2 is driven in an oscillatory movement about a shaft '7 by means of a treadle member secured to the said shaft. In order to determine the direction of rotation of the wheel 6, the shaft 8 thereof carries a ratchet device 9 which permits rotation of the shaft 8 in only Patented Se t; 16, 1958 one direction. The part 2 maybe connected to the shaft 7 by way of a spline 7b in aperture 711 of given length, so that the part 2 can move towards the parts 1 and 3 in the direction of length of and with respect to the shaft 7 without these magnets contacting with one another. During'the oscillatory movement of the part 2, only one magnet thereof, due to rotation of the parts 1 and 3 being possible in only one direction, is coupled to that magnet of the parts 1 and 3 of which the possibility of rotation coincides with that of the oscillatory arrangement. This coupling is intensified due to the coupled parts being subject to mutual attraction, so that the part 2 is as close as possible to the part 1 or 3 coupled therewith. The said mutual attraction varies between the slipping circuits, so that its mean value is zero. Due to the large spacing between the slipping parts, the amplitude of the said varying attraction is small only.

However, in Fig. 2 the part 2 is preferably immovable in the direction of length of the shaft 7 while a minimum air-gap exists between the parts.

When the direction of the oscillatory motion of the part 2 reverses, the coupling initially present starts to slip and the parts which were slipping hitherto are coupled synchronously. The above-mentioned arrangement may advantageously be used, for example, for driving a treadle sewing-machine in which the treadle 10 is operated by the feet, the rotary drive of the machine being provided by the shaft 8.

In Fig. 2, parts 11, 12 and 13 are arranged in a similar manner as in Fig. l and comprise a multiplicity of magnets. The drive in this case takes place by means of a shaft 14 of a conical wheel 15, which rotates in one direction, so that the conical wheels 16 and 17 connected to the magnets 11 and 13 are driven in a rotary manner in the opposite sense. The magnet 12 comprises a projection 18 which may co-operate with a stop 19 rigidly connected to the arrangements. During fthe rotation of the shaft 14, the part 12 is coupled to either of the parts 11 and 13 until the projection 18 abuts against the stop 19. The stop 19 is of the resilient type and causes reversal of the direction of movement of the part 12. As a result thereof, the part 12 is coupled to another part and thus driven in an oscillatory manner. Said arrangement may be used, for example, for driving a radar aerial which must be adapted to swing through a given angle about a shaft. It is also possible for the part 12 to be connected by means of one or more springs instead of via stop 19 to the fixed part of the arrangement.

What is claimed is:

l. A device for converting a tangentially oscillating movement about one shaft to a rotational movement of another shaft and viceoversa comprising a first part on said one shaft including a permanent magnet, a second part on said one shaft including a permanent magnet mechanically coupled to said first part, said first part rotating in one direction and said second part rotating in an opposite direction, a third part on said one shaft and positioned between said first and second parts and including a permanent magnet which performs a tangentially oscillating movement and which during one direction of movement is magnetically coupled to said first part and slips with respect to said second part, and during the opposite direction of movement is magnetically coupled to said second part and slips with respect to said first part.

2. A device for converting a tangentially oscillating movement about a shaft to a rotational movement and vice versa as claimed in claim 1 wherein said magnets are disc-shaped, arranged co-axially side by side, and magnetized in an axial direction, and said third part being adapted for limited translation with respect to said first and second parts whereby said parts which slip relative to each other exert only a small varying magnetic force upon one another. i

3. A device for converting a tangentially oscillating movement about a shaftwto a rotational movement and vice versa as claime ci inclaim 1 wherein said magnets are disc-shaped, arranged co-ax ially side by side, and magnetized in an axial direction, said third part being rigidly secured in an axial direction with respect to the 10 other parts, the parts, as measured along the pitch circle,

' having a plurality of permanent magnet poles of alternately varying sign.

' 4. A device for converting a tangentially oscillating movement about a shaft to a rotational movement and vice versa as claimed in claim 1 further comprising a fixed portion, yieldable means mounted on said fixed portion and co-acting with said third part to cause periodic reversal of direction of movement of said third part.

" I No references cited. 

